Dick karmiggelt
by



May 17, 1966 M, SCHRDER ET AL 3,252,120

PHOTOELECTRI C CELL Filed Jan. 28, 1963 INVENTORS HERMAN M. SCHRDER 7'DICK KRMIGGELT BY o GENT

PHTOELECTRIC CELL Herman Mathieu Schrder and Dick Karmiggelt,Emmasingel, Eindhoven, Netherlands, assignors to North American PhilipsCompany Inc., New York, N.Y., a

corporation of Delaware Filed Jan. 28, 1963, Ser. No. 254,201 Claimspriority, application Netherlands, Feb. 5, 1962, 274,386 12 Claims. (Cl.3381-19) The invention relates to an electric circuit element, moreparticularly a photo-electric cell or light-dependent resistorcomprising a preferably elongated body in a tubular envelope fittingaround the body with a certain amount of clearance space, in which,viewed in a cross section, the clearance space around the periphery ofthe body inside the envelope is filled, at 'least over part of theheight of the body, with a soft or viscous mass.

The photosensitive active element or body, which frequently comprises anelongated, e.g. plateor rod-shaped, body, owing to the sensitiveness ofits electrical properties to atmospheric influences, must be screened bya viscous or soft mass in a further envelope.

With a view to the use of the electric circuit element, the envelopemust have a minimum size, matching the shape and size of the activebody. This-involves the problem of filling uniformly the usually verysmall clearance in cross section over theheight of the body with aviscous or soft mass in order to obtain a uniform protection of thesensitive body parts. Since the opening of such an envelope to be closedis located comparatively near the body, there is furthermore the problemofvembedding the body in the filling mass, frequently a silicoorganicgrease, so that the filling mass'does not soil or smear the edge of theopening to be closed owing to `lack of uniformity in the filling, whichwould involve difficulties in adhesion during the subsequent sealing ofthe envelope.

In the manufacture of eg. photo-electric cells having a plate-shaped,electroded, photo-sensitive body this body may be embedded in a viscousmass and be introduced into a at, glass tube, which is open at one endand fits around said body with a certain amount of clearance, by

' slipping the photo-sensitive body into said tube, which has previouslybeen filled with the mass to an extent such that after the introductionof the body the mass fills the tube to the desired height upto thedesired distance from the opening. In carrying out this method ofembedding by hand, it appeared that along the narrow side walls thefilling mass was pushed upwards to a greater height than along the broadfront or' rear walls, thus smearing the edge of the opening to beclosed. With some forms of photo-electric cells this difficulty could beavoided by embedding the body not by hand but by centrifugal force. Withother embodiments, however, e.g. those in which the body to be embeddedconsisted of a metal support with a photo-sensitive plate attachedthereto, the ylack of uniformity and soiling of the edge were found tooccur even in the case of introduction by centrifugal force.

From experiments -carried out in connection with the invention it wasfound that said non-uniform filling is inter alia due to the fact thatthe clearance space available, viewed in across section, along theperiphery of the body exhibits local differences. With the aforesaidfiat photo-electric cells for example, there is preferably -left agreater clearance along the narrow side walls than on 'United StatesPatent Y O 3,252,120 Patented May 17|, 1966 lCe the broader front andrear walls, since the distance between the side walls cannot besatisfactorily controlled accurately in the manufacture of the envelope.If a small clearance is desired in a given direction in a cross section,it may be desirable to provide a larger clearance in another directionin the cross section in order to simplify the introduction of the bodyinto the envelope. It has furthermore been found that the irregularpushing-up of the filling mass was even worse and could not be avoidedby centrifugal force in the event of too great a difference in specificweights of the body and filling mass, which is the case for example withphoto-electric cells having a cooling plate fastened to thephoto-sensitive body.

On the basis of these results the invention has for its object interalia to provide a simple and efficacious embodiment of an electriccircuit element, particularly a photo-electric cell, which permits ofavoiding said difficulties in manufacture in a simple manner and toprovide, in addition, suitable methods of manufacturing such an electriccircuit element.

With an electric circuit element, particularly-a photoelectric cell ofthe shape described above, the clearance space in the plane of the crosssection along the periphery of the body exhibits differences and inaccordance with the invention the embedded body is locally provided,along its height, with one or more extensions, which partly fill in thelocal cross sectio'n the placesv of greater clearance space. Theinvention thus permits of manufacturing circuit elements with thedesired differences in clearance spaces between the envelope and thebody and of compensating by the presence of the local extensions for thedifferences in clearance spaces in a simple .manner to an extent suchthat a uniform filling of the viscous or soft mass is obtained withoutsmearing the opening to be sealed. With the manufacture of e.g.photo-electric cells it was now found to be possible to embed thosestructures also by hand, which could be embedded only by centrifugalforce without smearing the opening. In such an embodiment e.g. of aphoto-electric cell, in which case the invention is particularlyinteresting, the body has the shape of a plate and is formed, in thecase of a photoelectric cell, at least partly by a photo-sensitive plateprovided with-an electrode system, while the envelope is formed by afiat tube surrounding the body with a certain amount of clearance space.According to the invention this embodiment is characterised in that theclearance space in a cross-section at the narrow side walls of the attube is larger than that at the front-and at the rear walls, while atthe edges of the plate-shaped body, along its height, one or moreextensions are provided, which partly fill the clearance spaces alongthe two side walls in the local crosssection and are located oppositeeach other. The body may be composed of a plurality of parts or layer.The invention may also be applied in a similar manner to aphoto-electric cell of the shape described above, in which thephoto-sensitive plate is arranged ona supporting plate, preferablyof-'glass or ceramic material. It wasl furthermore found, by surprise,to be possible to fill uniformly such embodiments of circuit elements,for example photo-electric cells in which the mass weight between thebody and the viscous mass, for example owing to the presence of a metalcooling plate in the body, exhibited such differences that the bodycould not be embedded by centrifugal force without in- -volving the saiddifficulties, by using the extensions and also owing to the brakingeffect of the contraction of the clearance space. With an advantageousembodiment of such a photo-electric cell in the aforesaid, fiat tubularenvelope the body is formed mainly by an electroded photo-sensitivebody, Which is arranged, if desired with the interposition of an`insulating layer, on part of metal cooling strip, for example ofcopper.

- The extensions may be formed, for example, by locally thickened par-tsof a ring surrounding the body or they may be provided locally on theedge of the body by punching. In a particular embodiment of theinvention, in which the body has the shape of a plate and the envelopeis formed by a fiat tube having a larger clearance spaced along the `twoside walls, the edges of the plate-shaped body are held in metalclamping bodies, which may serve at the same time as electrode voltagesupplies and which are provided locally by extensions formed'by tags,which may be formed from the body itself by punching. In order tosimplify the introduction of the body into the envelope, the extensionsare preferably at an angle of`less than 90 to the edges of the body, andare orientated towards .the sealing area or open end lof the envelope.The extensions may engage the wall of the envelope, so that a furtherbraking effect in the embedding operation is obtained. However, in orderto avoid a dierence in the braking effect owing to tolerances in themeasurements of the section of the envelope, the extensions arepreferably provided so that in the local cross section they do not touchsimultaneously the inner wall of the envelope. In order to ensure anoptimum, uniform embedding, .preferably more than two extensions areprovided along the embedded height at regular intervals, the number ofextensions being higher the greater is the height to be ernbedded. Oneof the extensions is preferably provided on or near Athat part of thebody which comes first into contact with the viscous mass during theembedding operation.

The manufacture may be carried out so that the body is first slippedinto the envelope, after which the grease is introduced and distributedfor example by centrifugal force, while the extensions have aneffectconducive to the uniform distribution. However, the embedding operationis preferably carried out by slipping the body with the extensionsdescribed above into an envelope previously filled with the mass, whichmay, in some cases, be carried out manually and preferably bycentrifugal force.

The invention will now be described more fully with reference to a fewembodiments and the diagrammatic drawing.

FIGS. la, 1b, 1c, show one embodiment of a photoelectric cell in alongitudinal sectional view, a longitudinal cross sectorial view at theplace of the clamping bodies'. and in a further transverse sectionalview, respectively.

FIG. 2 shows diagrammatically a stage of the manufacture of thephoto-electric cell shown in FIG. l.

The invention will first be described with reference to a particularembodiment of a photo-resistance cell of the kind shown in FIGS. 1a, 1band 1c.

The envelope consists of an elongated, flat glass tube 1, open at thebottom side, the external height of which is about 40 mms., while theexternal section has the dimensions mms. x 5 mms. This glass tube 1,which has a wall thickness of about 0.8 mm., accommodates with a certainamount of clearance a plate-shaped photoresistance body `2, for exampleof CdS, having a height of 32 mms. and a cross section of 11 x l mms?.On one side 3 of the photo-resistance plate 2 there is provided anelectrode line system formed by two combshaped, interlaced lineelectrodes 4 and 5, applied by vaporisation and having a thickness offor example 5 x 0.5M. The other side 6 of the photo-resistance plate 2is fastened by means of an adhesive layer 7 for example of an epoxyresin, having a thickness of 0.1

mm., to part of a metal cooling plate 8, for example of copper, having athickness of about 1.4 mms. ther part 9 of said cooling plate projectsbeyond the sealed opening for conducting heat away and has an opening 10for fastening to a chassis. The seal consists of a synthetic substance11, for example an epoxy resin, comprising a filling plate 12 of quartzfor compensating the expansion of the cooling plate part 9, also takento the outside.

The photo-resistance plate 2 and the cooling plate 8 are held on thesides in U-shaped clamping bodies 13 and 14, having a thickness of 0.2mm., for example of copper or nickel and the assembly thus constitutes abody, which ts in the envelope 1 with a certain amount of play. O n thefront side 3 each of said clamping members 13 and 14 is electricallyconnected to one of the comb-shaped electrodes 4 and 5 respectively. Theclamping members 13 and 14 are electrically insulated lfrom the coolingplate 8 by means of a mica plate 15 of 0.2 mm. in thickness (see FIG.1c). The clamping members 13 and 14 terminate on the bottom side insupply conductors 16 and 17, which are also taken to the outside throughthe seal. the edges bythe clamping members 13 and 14 and for-med by Ithephoto-resistance plate 2, the adhesive 'layer 7, the cooling part 8 andthe mica plate 15, has, viewed in a cross section (see FIG. 1c) a smallclearance space which differs along the periphery of the body withrespect to the envelope 1. The clearance space between the rear envelopewall and the mica plate 15 and that between the front envelope wall andthe active side 3 of the body is not more than '0.3 to 0.4 mm., whereason either side of the body between Ithe side walls of the envelope 1 andthe clamping members 13 and 14 respectively a clearance space is left,the section of which is approximately semi-circular and has a radius ofabout 1 mm. The composite body is embedded substantially uniformlythroughout its height in a soft or viscous mass 18, which may consist ofa Silico-organic grease, for example Dow Corning High-Vacuum Grease, upto the proximity of the seal, Where a small air chamber 19 is left as anexpansion space for the grease.

In order to obtain this uniform embedding `four metal l extensions 20are provided at regular intervals along the height of the body at theplace of the larger clearance space on the sides on either side of thebody, sa-id extensions filling partly, inthe local cross section (seeFIG. 1c) the clearance spaces on Ithe sides and thus substantiallyleveling out the clearance in vthe cross section along the periphery.Said extensions are shaped in the form of tags, which are integral withthe clamping members 13 aud 14 and are obtained from the sides of saidclamping members by local embossed parts, which may be seen from FIG.1b, where the remaining cavities 21 in the sides of the clamping member13 are shown. In order to simplify the embedding of the body theextensions 20 are at an angle of less than 90 to the sides and areorientated towards the seal. One pair of extensions is provided on theupper side of the body,

i.e. on that part which comes first into contact with the viscous 4orsoft mass 18 during the embedding operation (see also FIG. 2). In theembodiment shown in FIGS. 1a, 1b and 1c these extensions 20 are arrangedso that they do just not touch the inner wall of the envelope 1 (seeFIG. 1c). However, the extensions 20 may protrude further so that theylocally engage the inner wall, in which case a' sometimes desirableadditional, advantageous braking effect along the Wall can be obtained.Owing to these extensions 20 a uniform filing along the periphery of andthroughout the height of the body may be obtained during embedding bycentrifugal force although the clearance spaces are different and themass weight of the body considerably exceeds that of the filling mass 18owing to the provision of the cooling plate 8, 9.

A fur- The body bounded at f body to be embedded.

FIG. 2 shows diagrammatically a stage of the manufacture yof aphoto-electric cell shown in FIGS. la,4 1b and 1c.

The envelope 1 is held in the holder 30, shown diagrammatically andintroduced into a centrifugal machine 31, which is.adapted to rotateabout the shaft 32, the upper end of the envelope 1 being closed andbeing spaced apart from the shaft 32 by a distance of about 13 cms. Theenvelope 1 is previously filled with a quantity of soft mass 18 to anextent such that, after the body is embedded, the clearance is uniformlyfilled up to the height indicated in FIG. 1a. On the filling mass 18 isdisposed the body to be embedded, which consists of the clamping members13 and 14 and the mica plate held thereby, the cooling plate (8, l9),the adhesive layer and the photo-sensitive plate 2. The body to beembedded is provided with the extensions 20, as is shown in FIGS. 1a, 1band 1c. By centrifuging with a speed of 2200 rev./min. for about 5minutes the plate-shaped body is uniformly embedded in the filling mass18 so that the configuration shown in FIGS. la, 1b and 1c is obtained,after which the opening is sealed in the manner described with referenceto FIGS. la., lb and 1c.

The embodiment'shown in FIGS. la, 1b, 1c and 2 is concerned with a flat,glass envelope and a plate-shaped Itl will be obvious that the inventionmay also be carried out with other circuit elements, for examplesemi-conductor devices and other shapes of envelopes and/ or bodies, inwhich similar problems are brought about by the difference in clearancespaces along the periphery of the body to be embedded. For example asimilar problem is involved in using a tubular envelope having acircular section, fitting with a certain amount of play about arod-shaped body, for example a semi-conductor body having rectangularsection and different lengths of the sides, so that the clearance spacebetween one pair of sides and the envelope is unequal to that betweenthe other pair of sides and the envelope. In order to acquire a uniformembedding local extensions are used, which partly fill the place oflarger clearance. It will furthermore be obvious that within the scopeof the invention many variants are possible to those skilled in the art.The invention may also be applied for example to aconfiguration as shownin FIG; 1, when the cooling plate 8 is omitted and the body to beembedded is formed substantially only by the photosensitive plate.According as the height of the body to be embedded is greater, thegreater will be the effectiveness of the invention.

What is claimed is:

1. An electrical device comprising a tubular envelope having an openend, anv electrically-active body containing electrodes disposed withintheenvelope and'defning between the periphery of the body'and the insidewall of the envelope an annular clearance space having v a non-uniformcross section, a grease like filling mass disposed in the clearancespace and extending at least over the greater part of the length of thebody, at least one projection extending from the body into that part ofthe non-uniform annular clearance space which is greater than adjacentparts of the clearance space to obtain more uniform disposition of thefilling mass within the clearance space, means sealing the open end ofthe envelope, and lead-in conductors passing through the sealing meansand connected to the said electrodes.

2. An electrical device comprising an elongated tubular envelope havingan open end, an elongated body including a photoconductive elementcontaining electrodes disposed within the envelope and defining betweenthe periphery of the body and the inside wall of the envelope an annularclearance space having a non-uniform cross section, a paste-like massdisposed in the clearance space and extending at least over the greaterpart of the length of the body, plural spaced projections distrib'- utedalong the length of the body and extending from the body into that partof the non-uniform annular clearance space which is greater thanadjacent parts of the clearance space to obtain more uniform dispositionof the paste-like mass within the clearance space, said elongated bodyhaving a substantially greater specific weight than that of thepaste-like mass, means sealing-the open end of the envelope, and lead-inconductors passing through the sealing means and connected to the saidelectrodes.

3. A device as set forth in claim 2 wherein a resinous I nass seals'theopen end leaving an empty space adjacent the paste-like mass to providefor its expansion.

4. A device as set forth in claim 3 wherein an expansioncoxnpensationmember is embedded in the resinous mass, and the latter is an epoxyresin.

5. A photoconductive device comprising an elongated tubular envelopewith a fiattened oval cross section and having an open end, an elongatedplate-like body including a photoconductive element containingelectrodes disposed within the envelope and defining between theperiphery of the body and the inside wall of the envelope a generallyoval, annular clearance space having a nonuniform cross section withlarger areas along the envelope side walls than along the broader frontand rear walls, a grease-like mass disposed in the clearance space andextending over the Whole length of the body, -the open end of saidenvelope being free of the grease-like mass, plural projectionsextending from the edges of the body into the larger areas on both sidesof the annular clearance space to obtain more uniform disposition of thegrease-like mass within the clearance space, a sealing material fillingand sealing the open end of the envelope and adhered to the inner wallsthereof, and lead-in conductors passing through the sealing material andconnected to the said electrodes.

6. A device as set forth in claim 5 wherein the photoconductive elementcomprises a photoconductive plate, a metal'cooling strip is providedtogether with means securing together in electrically-insulatingrelationship said cooling strip and photoconductive plate along thelength of the said plate, said body with the cooling strip having agreater specific weight than that of the greaselike mass.

7.- A device as set forth in claim 5 wherein at least two spacedprojections are provided along each edge of the plate-like body.

8. A device as set forth in .claim 5 wherein projections are providedatleast at the end of the plate-like body remote from the open end.

9, A photoconductive device 'comprising an elongated tubular envelope ofinsulating material with a flattened oval cross section and having anopen end, an elongated plate-like body including a photoconductiveelement containing electrodes disposed within the envelope and definingbetween the periphery of the body and the inside wall of the envelope agenerally oval, annular clearance space having a non-uniform crosssection with larger areas along the envelope side Walls than along thebroader front and rear Walls, a grease-like mass disposed in theclearance space and extending over the Whole length of the body, theopen end of said envelope being free of the grease-like mass, metalclamping members extending along and in clamping engagement with bothedges of the plate-like body, plural projections extending from theclamping members into the larger areas on bothsides of the annularclearance space to obtain more uniform'disposition of the grease-likemass within the clearance space, a sealing material filling and sealingthe open end of the envelope and adhered to the inner walls thereof, andlead-in conductors passing through the sealing material and connected tothe said electrodes.

10. A device as set forth in claim 9 wherein the projections constitutepunched-out tags of the clamping members.

' 7 11. A device as set forth in claim 9 wherein the projections extendpartly toward the sealed end of the envelope.

12. A device as set forth in claim 9 wherein at least some of theprojections are spaced from the envelope walls.

References Cited by the Examiner UNITED STATES PATENTS 1,941,493 1/1934Ruben 25o-212 10 8 Drugrnan 29-15564 Schwing 29-155.64 Haybail et al.338-18 Anderson 388-18 Karmiggelt et al. 338-15 X ANTHONY BARTIS, ActingPrimary Ex'amner. RICHARD M. WOOD, Examiner. I

W. D. BROOKS, H. T. POWELL, Assistant Examiners.

9. A PHOTOCONDUCTIVE DEVICE COMPRISING AN ELONGATED TUBULAR ENVELOPE OFINSULATING MATERIAL WITH A FLATTENED OVAL CROSS SECTION AND HAVING ANOPEN END, AN ELONGATED PLATE-LIKE BODY INCLUDING A PHOTOCONDUCTIVEELEMENT CONTAINING ELECTRODES DISPOSED WITHIN THE ENVELOPE AND DEFININGBETWEEN THE PERIPHERY OF THE BODY AND THE INSIDE WALL OF THE ENVELOPE AGENERALLY OVAL, ANNULAR CLEARANCE SPACE HAVING A NON-UNIFORM CROSSSECTION WITH LARGER AREAS ALONG THE ENVELOPE SAIDE WALLS THAN ALONG THEBROADER FRONT AND REAR WALLS, A GREASE-LIKE MASS DISPOSED IN THECLEARANCE SPACE AND EXTENDING OVER THE WHOLE LENGTH OF THE BODY, THEOPEN END OF SAID ENVELOPE BEING FREE OF THE GREASE-LIKE MASS, METALCLAMPING MEMBERS EXTENDING ALONG AND IN CLAMPING ENGAGEMENT WITH BOTHEDGES OF THE PLATE-LIKE BODY, PLURAL PROJECTIONS EXTENDING FROM THECLAMPING MEMBERS INTO THE LARGER AREAS ON BOTH SIDES OF THE ANNULARCLEARANCE SPACE TO OBTAIN MORE UNIFORM DISPOSITION OF THE GREASE-LIKEMASS WITHIN THE CLEARANCE SPACE, A SEALING MATERIAL FILLING AND SEALINGTHE OPEN END OF THE ENVELOPE AND ADHERED TO THE INNER WALLS THEREOF, ANDLEAD-IN CONDUCTORS PASSING THROUGH THE SEALING MATERIAL AND CONNECTED TOTHE SAID ELECTRODES.